Despite recent advances, development of nucleic acid (NA) therapies continues to be impeded by the challenges of effective delivery. GeneSegues, Inc. (GSI) has developed a nonviral delivery technology, sub-50 nanometer (s50) capsules, which co-opt the raft/caveolar uptake path for efficient intracellular delivery of NA drugs. The raft/caveolar path is an endogenous, intracellular transport mechanism that can efficiently deliver internalized complexes into the cell, avoiding the inflammation and drug degradation mechanisms that have consistently thwarted effective delivery of NA drugs. Exploiting this receptor-mediated, size-sensitive path is achieved with a novel capsule design comprised of a single-layer crystallized polymer shell which shields the NA drug, sterically stabilizes the shell, and targets the capsule. In liver, GSI has demonstrated initial proof-of-concept for liver-targeted, cell-subtype delivery of functional plasmid DNA. Hepatocyte-specific delivery in mice was demonstrated with s50 capsules employing asialoorosomucoid (ASOR) ligands targeting the asialoglycoprotein receptor (ASGPr), while delivery to LSEC's was achieved using hyaluronan (HA)-coated s50 capsules targeting the HA receptor for endocytosis (HARE). We now propose to initiate preclinical development of these liver-targeted, plasmid-bearing s50 capsules for therapeutic application. Additionally, in view of the promising therapeutic potential of RNAi, we propose to also synergistically assess the utility of s50 capsules for systemic in vivo delivery of therapeutic RNAi oligonucleotides to defined liver target sites. Therefore, our proposed specific aims are to (1) determine utility and safety of s50 hepatocyte-targeted capsules for systemic delivery of double and single stranded RNAi oligonucleotides, using a published siRNA sequence (siApoB-1) encapsulated in s50 ASOR-ligand capsules and (2) assess safety of LSEC-targeted s50 capsules for systemic delivery of plasmid DNA, using an epitope-tagged reporter gene encapsulated in s50 HA-ligand capsules. Biodistribution will be assessed by radiolabel for NA's delivered via HA-coated as well as ASOR-coated s50 capsules, and any evidence of early inflammatory responses will be assessed for plasmid and RNAi cargos. If successful, we expect this body of work will provide a solid framework for partnering with NIH and/or drug developers to move forward encapsulated NA therapies for liver disease. PUBLIC HEALTH RELEVANCE: Nucleic acid drugs offer much promise for treating diseases of the liver. However, delivering nucleic acids into disease cells of the liver is very problematic because (1) the liver is a heterogeneous organ with many different cell types, and (2) nucleic acids can trigger drug degradation and toxic reactions once inside the cell. We propose to further develop nucleic acid delivery technology capable of accessing and penetrating specific cell types within the liver, and of avoiding intracellular defenses, for effective treatment of liver disease.